1. Technical Field
The embodiments herein generally relate to wireless technologies, and, more particularly, to mobile television (TV) technologies.
2. Description of the Related Art
In Digital Video Broadcasting over Handheld (DVB-H) device systems, a time division multiplexing (TDM) based scheme, so called time-slicing, is introduced to reduce the average power consumption in DVB-H receiver. The concept of time-slicing is to send data in bursts using a significantly higher bit rate compared to the bit rate required if the data was transmitted continuously. Within a burst, the time to the beginning of the next burst (ΔT) is indicated. Between the bursts, the data of the elementary stream is not transmitted, allowing other elementary streams to use the bit rate otherwise allocated. This enables a receiver to stay active for only a fraction of the time, while receiving bursts of a request service.
The receiver can sleep for a period of time equal to ΔT before it wakes up again to receive the next burst. In order to wake up again after a period of time ΔT, the receiver has to keep a timer running. This timer times out after ΔT and wakes up the receiver. This timer requires a clock running on-chip during the sleep time, ΔT. This requires having a crystal oscillator (XO) and phase locked loop (PLL) circuits to be running on the chip, which consumes significant power.
Furthermore, before the arrival of the next burst, the receiver has to wake up a bit earlier to synchronize some PHY parameters; e.g., carrier and timing offset, transmit parameter signaling (TPS) information to determine the scattered pilots location for channel equalization, etc. The time required to re-synchronize these parameters determines how early the receiver has to wake up before the arrival of the next burst. The longer the re-synchronization time, the longer the receiver active time is during the burst reception and thus, the higher the average receiver power consumption. In order to reduce the average power consumption, it is essential to reduce the receiver re-synchronization time between bursts. To facilitate the re-synchronization process, an on-chip timer and several internal state registers have be needed to be active while the receiver is in the sleeping mode. This consumes additional power of running the XO, PLL circuits, and timer circuits between bursts. Accordingly, there remains a need for a re-synchronization technique that facilitates low power consumption in a DVB-H receiver.